Image forming device

Abstract

To provide a configuration that attaches a drum cartridge 10 to an apparatus main body, the configuration capable of preventing adhesion of toner to an LED 210 and preventing a reduction in the quantity of light incident on a light guide body 161.SOLUTION: A sealing member 240 has a through hole 241 through which, of a light guide body unit 16, 161b of the light guide body unit 16 closer to an LED 210 than one end in a longitudinal direction of a photoconductor drum penetrates. The sealing member 240 seals the space between the LED 210 and the other end side in the longitudinal direction of a drum cartridge 10 with respect to the penetration part 161b. The sealing member 240 is an elastic body and is formed such that an inner peripheral surface of the through hole 241 is in elastic contact with an outer peripheral surface of the penetration part 161b of the light guide body unit 16 that penetrates the through hole 241.SELECTED DRAWING: Figure 14

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus such as a copier, printer, facsimile, or a multifunction machine having multiple functions of these. [Background technology]

[0002] Conventionally, image forming apparatuses have been known that have a drum cartridge or process cartridge having a photosensitive drum as a photosensitive member that can be detachably attached to the apparatus body. Also, conventionally, an image forming apparatus has been known that includes an optical static elimination device that irradiates the surface of the photosensitive drum with light to eliminate electric charges on the photosensitive drum (Patent Document 1).

[0003] Patent Document 1 describes a configuration having a process cartridge that is detachable from the apparatus main body and that includes a light guide that guides light from a light source provided in the apparatus main body to the surface of a photosensitive drum. Patent Document 1 also describes a configuration in which the periphery of the light source is covered with a light-blocking member made of an elastic material to prevent light from the light source from leaking to the outside. In the configuration described in Patent Document 1, when the process cartridge is installed, an end of the light guide abuts against the light-blocking member, causing the light-blocking member to expand and contract. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-278395 Summary of the Invention [Problem to be solved by the invention]

[0005] Here, if scattered toner adheres to the light source, the light from the light source is blocked by the adhered toner, reducing the amount of light incident on the light guide and potentially reducing the static elimination effect of the photosensitive drum. In the configuration described in Patent Document 1, the light source is covered with a light-blocking member, making it difficult for scattered toner to adhere to the light source.

[0006] However, in the configuration described in Patent Document 1, there is a risk that the light blocking member may come into contact with the end of the light guide when the process cartridge (photosensitive unit) is installed, causing the light blocking member to deform and block part of the light incident surface of the light guide. In this case, there is a risk that the amount of light incident on the light guide may decrease, and the effect of eliminating static electricity from the photosensitive drum may be reduced.

[0007] The present invention aims to provide a configuration in which a photosensitive unit is attached to the device main body, which can suppress toner adhesion to the light source and suppress a decrease in the amount of light incident on the light guide. [Means for solving the problem]

[0008] The present invention One aspect The device body, the rotating photosensitive member, and the photosensitive member Rotation axis The said Rotation axis direction in Light incident from one end is guided to the surface of the photoreceptor. Light guide member and By moving along the rotation axis direction a photosensitive unit that is detachable from the device body; Materials Before Note 1 At the end On the light incident surface a light source for irradiating light; Hold the light source , the above Light guide member Before Note 1 end The part is inserted Through holes It is an elastic body having Sealing member A holding member having and, When the light guide member is inserted into the through hole , the inner peripheral surface of the through hole and the light guide member of At the one end Outer surface and teeth abutment and the gap between the inner peripheral surface and the outer peripheral surface is sealed. Characterized by It is an image forming device . [Effects of the Invention]

[0009] According to the present invention, by mounting the photosensitive unit to the main body of the apparatus, it is possible to suppress toner adhesion to the light source and also to suppress a decrease in the amount of light incident on the light guide. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view showing a schematic configuration of an image forming apparatus according to a first embodiment. [Figure 2] FIG. 2 is a perspective view of the drum cartridge according to the first embodiment. [Figure 3] FIG. 1 is a cross-sectional view showing a schematic configuration of a drum cartridge according to a first embodiment. [Figure 4] FIG. 2 is an enlarged perspective view of a part of the drum cartridge according to the first embodiment. [Figure 5] FIG. 2 is a perspective view of a part of the drum cartridge according to the first embodiment, seen from the incident surface side of the light guide. [Figure 6] FIG. 2 is a diagram showing an end face on the incident surface side of the light guide according to the first embodiment. [Figure 7] FIG. 2 is a perspective view showing a light source unit according to the first embodiment. [Figure 8] FIG. 2 is a perspective view showing a state in which a light guide of the drum cartridge according to the first embodiment faces a light source. [Figure 9] FIG. 3 is a side view showing a state in which the light guide of the drum cartridge according to the first embodiment faces a light source. [Figure 10] FIG. 2 is a perspective view showing a state in which a sealing member is attached to the light source unit according to the first embodiment. [Figure 11] FIG. 2 is a front view of the sealing member according to the first embodiment. [Figure 12] FIG. 2 is a front view of the holding member according to the first embodiment. [Figure 13] FIG. 4 is a perspective view showing a state in which the light guide of the drum cartridge according to the first embodiment penetrates a sealing member and a holding member and faces a light source. [Figure 14] FIG. 4 is a cross-sectional view showing a state in which the light guide of the drum cartridge according to the first embodiment penetrates a sealing member and a holding member and faces a light source. [Figure 15] FIG. 10 is a perspective view of a light source unit according to a second embodiment. [Figure 16] FIG. 10 is a perspective view of a support member according to a second embodiment. [Figure 17] FIG. 10 is a perspective view showing a state in which a light guide of a drum cartridge according to a second embodiment faces a light source. [Figure 18] FIG. 10 is a side view showing a state in which a light guide of a drum cartridge according to a second embodiment faces a light source. [Figure 19] FIG. 10 is a perspective view showing a state in which a sealing member is attached to a light source unit according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] First Embodiment The first embodiment will be described with reference to Figures 1 to 14. First, the schematic configuration of an image forming apparatus according to this embodiment will be described with reference to Figure 1.

[0012] [Image forming equipment] The image forming apparatus 1 of this embodiment is an electrophotographic tandem-type full-color printer equipped with four image forming units 100, each having a photosensitive drum 12 as an image carrier. The image forming apparatus 1 forms a toner image (image) on a recording material in response to an image signal from a document reading device 110 connected to the apparatus main body 1A or a host device such as a personal computer connected to the apparatus main body 1A so as to be able to communicate with the apparatus main body 1A. Examples of the recording material include sheet materials such as paper, plastic film, and cloth. In the following description, the recording material will be described as a sheet. The four image forming units 100 form yellow, magenta, cyan, and black toner images, respectively. The four image forming units 100 of the image forming apparatus 1 have substantially the same configuration, except for the different developing colors.

[0013] The image forming unit 100 includes a drum cartridge (photosensitive unit) 10 having a photosensitive drum 12 as a photosensitive member, and a developing unit 20. The photosensitive drum 12 is a cylindrical photosensitive member that rotates clockwise in FIG. 1. The surface of the photosensitive drum 12 is uniformly charged by a charging roller 13 as a charging device, and then an electrostatic latent image is formed on the surface by a laser scanner 22 as an exposure device driven based on transmitted image information signals. The electrostatic latent image is visualized as a toner image by the developing unit 20. The toner images on the photosensitive drum 12 of each image forming unit 100 are sequentially transferred to an intermediate transfer belt 30 as an intermediate transfer member by a primary transfer roller 31 applying a predetermined pressure and electrostatic load bias. After transfer, any small amount of residual toner remaining on the photosensitive drum 12 is removed and collected by a cleaning blade 14, and the developing unit 20 is prepared for the next image formation. Toner is replenished to the developing unit 20 from a toner cartridge 21.

[0014] Meanwhile, sheets P are fed one by one from the feeding cassette 40 and conveyed to the pair of registration rollers 50. The leading edge of the sheet P is looped by following the nip of the pair of registration rollers 50, thereby correcting any skew. The pair of registration rollers 50 then conveys the sheet P between the intermediate transfer belt 30 and the outer secondary transfer roller 33 in synchronization with the toner image on the intermediate transfer belt 30. The color toner image on the intermediate transfer belt 30 is transferred to the sheet P by applying a predetermined pressure and an electrostatic load bias at the nip between the drive roller 32 and the outer secondary transfer roller 33, which are disposed opposite each other across the intermediate transfer belt 30. After transfer, any small amount of residual toner remaining on the intermediate transfer belt 30 is removed and collected by the cleaning blade 34, preparing for the next image formation. The toner image transferred to the sheet P is fixed by heat and pressure in the fuser 60, and then discharged onto the discharge tray 80 by the pair of discharge rollers 70.

[0015] [Drum cartridge] Next, the configuration of the drum cartridge 10 will be described with reference to Figures 2 to 6. As shown in Figures 2 and 3, the drum cartridge 10 as a photosensitive unit has a photosensitive drum 12, a charging roller 13, a cleaning blade 14, and a cleaning roller 15, which are integrally held in a drum container 11. The drum container 11 as a photosensitive container houses the photosensitive drum 12, the charging roller 13, the cleaning blade 14, and the cleaning roller 15.

[0016] Such a drum cartridge 10 is detachable from the device main body 1A (FIG. 1) and can be replaced for maintenance, etc. In this embodiment, the drum cartridge 10 can be inserted into and removed from the device main body 1A in the front-to-back direction of the paper surface of FIG. 1. That is, the drum cartridge 10 can be inserted into and removed from the device main body 1A along the rotation axis direction of the photosensitive drum 12.

[0017] The photosensitive drum 12 is rotatably held in the drum container 11 via a bearing (not shown), and the photosensitive drum 12 is provided with a coupling (not shown) for receiving drive force from the apparatus main body 1A to rotate. As shown in FIG. 4 , the charging roller 13 and the cleaning roller 15 are rotatably supported by a bearing 131, and are pressed against the photosensitive drum 12 by a pressure spring 132. When the photosensitive drum 12 receives drive force from the apparatus main body 1A to rotate, the charging roller 13 rotates due to friction with the photosensitive drum 12, and when the charging roller 13 further rotates, the cleaning roller 15 rotates due to friction with the charging roller 13. As a result, the surface of the charging roller 13 is cleaned by the cleaning roller 15.

[0018] 3, a cleaning blade 14 is fixed to the drum container 11. A transport coil 17 is provided near the cleaning blade 14 to transport the toner collected by the cleaning blade 14 and discharge it from the drum cartridge 10 to the apparatus main body 1A. The transport coil 17 is disposed within a transport path formed by the drum container 11. A transport drive gear (not shown) for rotating the transport coil is provided at one end of the transport coil 17, and the transport drive gear is drivingly connected to the photosensitive drum 12 by a drive train (not shown).

[0019] Furthermore, a light guide unit 16 that functions as an optical static eliminator 200 (FIG. 13) is fixed to the drum container 11. The optical static eliminator 200 includes the light guide unit 16, a light source unit 201, and a sealing member 240, which will be described later. The optical static eliminator 200 of this embodiment irradiates light onto the surface of the photosensitive drum 12 after a toner image has been transferred from the photosensitive drum 12 to the intermediate transfer belt 30, thereby eliminating residual charges on the photosensitive drum 12.

[0020] If the next image is formed while residual charge remains on the surface of the photosensitive drum 12, it may remain as an afterimage on the image, but by removing the residual charge using the optical static eliminator 200, it is possible to suppress image defects caused by such afterimages. For this reason, in this embodiment, as shown in Figure 3, the light guide unit 16 is disposed upstream of the cleaning blade 14 in the rotation direction (arrow direction) of the photosensitive drum 12 and downstream of the primary transfer roller 31 (Figure 1).

[0021] [Light guide unit] As shown in FIGS. 5 and 6, the light guide unit 16 of this embodiment is a rod-shaped light guide made of a light-transmitting material such as acrylic resin. (light-guiding member) The light guide unit 16 is made up of a protective member 161 that covers the circumferential surface of the light guide 161 except for the portion that faces the photosensitive drum 12. The light guide unit 16 is provided in the drum cartridge 10. This will be described in more detail.

[0022] The light guide unit 16 is disposed along a longitudinal direction (rotational axis direction) that intersects with the rotational direction of the photosensitive drum 12. In this embodiment, the light guide unit 16 is disposed adjacent to the photosensitive drum 12, substantially parallel to the rotational axis direction of the photosensitive drum 12, and opposed to the entire longitudinal area of the photosensitive drum 12.

[0023] Furthermore, a portion of one longitudinal end of the light guide unit 16 protrudes outward from the drum container 11. In this embodiment, the one longitudinal end is the end on the rear side in the insertion / removal direction of the drum cartridge 10 (the rear side of the image forming apparatus 1). The front side of the image forming apparatus 1 is the side on which an operator such as a user operates the image forming apparatus 1, and is the front side of the paper in FIG. 1. On the other hand, the rear side of the image forming apparatus 1 is the opposite side to the front side, and is the rear side of the paper in FIG. 1.

[0024] The portion of the light guide unit 16 that protrudes from the drum container 11 at one longitudinal end has a shape as shown in Fig. 6 when viewed from the longitudinal end. That is, the protective member 162 has a semicircular portion 162a with a semicylindrical shape and an outer diameter of radius R1 above the center of the light guide 161, and a rectangular portion 162b with a generally rectangular shape that is continuous with the semicircular portion 162a below. The dimension of the rectangular portion 162b in the left-right direction in Fig. 6 is also R1. Furthermore, a generally T-shaped lower portion 164 is fixed to the lower side of the protective member 162.

[0025] The light guide 161 constituting the light guide unit 16 has a substantially cylindrical shape and is made of, for example, polycarbonate or acrylic, which is an insulating material with high light transmittance. The light guide 161 is prism-processed and is formed so as to effectively guide light entering from an incident surface 161a to the surface of the photosensitive drum 12. That is, one end face of the light guide 161 in the longitudinal direction serves as the incident surface 161a, and light entering from the incident surface 161a is reflected toward the photosensitive drum 12.

[0026] 3, an opening 163 is formed in a portion of a protective member 162 covering the light guide 161, the portion facing the photosensitive drum 12. As a result, light incident on the light guide 161 from the incident surface 161a is guided to the surface of the photosensitive drum 12 through the opening 163.

[0027] In this embodiment, as shown in FIG. 14, the incident surface 161a, which is an end face on one longitudinal end side of the light guide 161, is located closer to the other longitudinal end side than the end face of the protective member 162, which is an end face of the light guide unit 16. In other words, the protective member 162 existing around the incident surface 161a protrudes toward the one longitudinal end side. This makes it less likely that the incident surface 161a will come into contact with other members when, for example, installing the drum cartridge 10. However, the end face of the protective member 162 and the incident surface 161a may be located on approximately the same plane.

[0028] Furthermore, the light guide 161 may not be prism-processed, or the light guide unit 16 may be configured only with the light guide 161 without including the protective member 162. Furthermore, light sources, which will be described later, may be provided at both ends of the light guide 161 in the longitudinal direction, so that light incident from the incident surfaces at both ends is irradiated toward the photosensitive drum 12.

[0029] [Light source unit] The light source unit 201 is disposed in the apparatus main body 1A and supplies light to the light guide unit 16 of the drum cartridge 10. As shown in FIG. 7, the light source unit 201 is composed of an LED (Light Emitting Diode) 210 as a light source and a light source holding member 220. As shown in FIGS. 8 and 9, the LED 210 faces one longitudinal end of the light guide unit 16 when the drum cartridge 10 is attached to the apparatus main body 1A (FIG. 1). The light emitted from the LED 210 is incident on the incident surface 161a (FIG. 5) of the light guide 161 of the light guide unit 16.

[0030] In this embodiment, the light source unit 201 is provided only on one longitudinal end side of the light guide 161, but the LEDs 210 may be provided on both ends. The light source may be a light-emitting source other than an LED, and the shape of the LED 210 is not limited to the shape shown in Fig. 7, but may be, for example, a bullet-shaped head shape.

[0031] As described above, the drum cartridge 10 is inserted into and removed from the apparatus main body 1A along the rotation axis direction. As shown in Fig. 9, when the drum cartridge 10 is attached to the apparatus main body 1A, the LED 210 is spaced a distance A from the incident surface 161a at one longitudinal end of the light guide unit 16, which is the downstream end in the insertion direction of the drum cartridge 10. This prevents the LED 210 from coming into contact with the light guide unit 16 when the drum cartridge 10 is inserted or removed, thereby preventing damage to the LED 210.

[0032] Here, there is a risk that toner may scatter in the drum cartridge 10 and adhere to the LED 210. In recent years, there has been a demand for even faster processing speeds in image forming devices. As the image formation speed of the device increases, the rotation speed of the photosensitive drum also increases. To achieve the same optical destaticization effect on a photosensitive drum rotating at high speed as when it rotates at low speed, it is necessary to irradiate the photosensitive drum with more light. Therefore, if the light source's light output is increased, the temperature near the light source's light-emitting point increases locally due to the heat generated by the light source. If floating particles such as toner approach this point, the heat from the light source surface may melt the toner and cause it to adhere to the light source surface. If toner adheres to the light source surface, the fused toner blocks light, reducing the amount of light entering the light guide, preventing sufficient destaticization of the photosensitive drum and resulting in a deterioration in image quality. Therefore, in this embodiment, a sealing member 240 is used to seal the gap between the LED 210 and the drum container 11 of the drum cartridge 10 as follows.

[0033] [Sealing member] Next, the sealing configuration using the sealing member 240 of this embodiment will be described with reference to Fig. 10 to Fig. 14. In this embodiment, the light source unit 201 is provided with a sealing member 240 made of an elastic material, as shown in Fig. 10. That is, the sealing member 240 is held by a sealing member holding member 230 serving as a holding member, and the sealing member holding member 230 is fixed to the light source holding member 220 by, for example, adhesion.

[0034] The sealing member 240 is disposed on the front side (the side that emits light) of the LED 210. Therefore, the LED 210 is configured so that its periphery is almost entirely covered by the light source holding member 220, the sealing member holding member 230, and the sealing member 240, except for a through-hole 241, which will be described below.

[0035] The sealing member 240 is formed of a porous resin such as sponge, or an elastic material such as elastomer. Furthermore, as shown in FIGS. 10 and 11, a through-hole 241 is formed in the sealing member 240 at a position facing the LED 210 in the longitudinal direction. The through-hole 241 has a substantially circular shape with a radius R2 in a free state. The sealing member 240 also has a slit 242 that continues from the through-hole 241 to the outer circumferential surface of the sealing member 240. The slit 242 extends downward from the through-hole 241 and continues to the lower surface of the sealing member 240.

[0036] 12 and 14, the sealing member holding member 230 has a passing portion 231 through which the through portion 161b of the light guide unit 16 can pass. That is, the sealing member holding member 230 has a holding plate portion 232 disposed between the LED 210 and the sealing member 240. The passing portion 231, which is a hole passing through the holding plate portion 232, is formed at a position of the holding plate portion 232 facing the LED 210 in the longitudinal direction.

[0037] When the drum cartridge 10 is inserted into the apparatus main body 1A, the through-hole 161b, which is a part of the light guide unit 16 that protrudes downstream in the insertion direction from the drum container 11, passes through the through-hole 241 of the sealing member 240 and the passing portion 231 of the sealing member holding member 230. Then, as shown in FIGS. 13 and 14 , with the space between the drum container 11 and the light source unit 201 sealed by the sealing member 240, the incident surface 161a of the light guide 161 of the light guide unit 16 faces the LED 210. This will be described in detail below.

[0038] When the drum cartridge 10 is inserted into the apparatus main body 1A, the through-hole 241 of the sealing member 240 is penetrated by the through-hole 161b of the light guide unit 16. The through-hole 161b is a part of the light guide unit 16 that is closer to the LED 210 (light source side) than one longitudinal end of the photosensitive drum 12. In this embodiment, a part of the light guide unit 16 that protrudes from one longitudinal end of the drum container 11 toward the LED 210 serves as the through-hole 161b.

[0039] The outer shape of the through-hole 161b is the shape shown in FIG. 6. That is, the through-hole 161b has a semicircular portion 162a, a rectangular portion 162b, and a lower portion 164. The centers of the LED 210, the through-hole 241, and the semicircular portion 162a of the through-hole 161b are generally aligned when viewed from the longitudinal direction. The center of the semicircular portion 162a is aligned with the center of the light guide 161. Therefore, when the drum cartridge 10 is attached to the apparatus main body 1A, as shown in FIG. 14, the center of the light guide 161 is generally aligned with the center of the LED 210, and the incident surface 161a of the light guide 161 faces the LED 210.

[0040] Such a through hole 241 is smaller than the cross-sectional shape of the through portion 161b of the light guide unit 16. That is, when the cross-sectional shape of the through portion 161b, which is a part of the light guide unit 16, is projected onto the sealing member 240 in the longitudinal direction, the through hole 241 in a state where the through portion 161b does not penetrate (free state) is within the range of the cross-sectional shape of the through portion 161b. Moreover, the area of the through hole 241 is smaller than the cross-sectional area of the through portion 161b.

[0041] Specifically, the radius R2 of the through hole 241 in the free state shown in Fig. 11 is smaller than the radius R1 of the semicircular portion 162a of the light guide unit 16 shown in Fig. 6. That is, as shown in Fig. 14, R1>R2. Note that Fig. 14 shows the through hole 241 of the sealing member 240 in the free state. In this embodiment, R1=2.5 mm, and R2=2.0 mm.

[0042] With this configuration, when the through-hole 241 penetrates the through-hole 161b of the light guide unit 16, the sealing member 240, which is an elastic body, deforms to fit the outer shape of the through-hole 161b. As a result, the inner circumferential surface of the through-hole 241 elastically abuts against the outer circumferential surface of the through-hole 161b that penetrates the through-hole 241. The sealing member 240 can then seal the gap between the LED 210 and the other longitudinal end side of the through-hole 161b of the drum cartridge 10, i.e., the upstream side in the insertion direction. In this embodiment, the sealing member 240 seals the gap between the LED 210 and the drum container 11, inside which the photosensitive drum 12 is disposed.

[0043] In particular, in the present embodiment, the through-hole 161b, which is a part of the light guide unit 16, penetrates the through-hole 241 of the sealing member 240. Therefore, when the drum cartridge 10 is attached to the apparatus main body 1A, it is possible to prevent a part of the sealing member 240 from deforming and blocking a part of the incident surface 161a of the light guide 161. Furthermore, by elastically abutting the inner circumferential surface of the through-hole 241 with the outer circumferential surface of the through-hole 241, it is possible to improve sealing performance. Therefore, when the drum cartridge 10 is attached to the apparatus main body 1A, it is possible to prevent toner from adhering to the LED 210 and to prevent a decrease in the amount of light incident on the light guide 161.

[0044] Furthermore, since the sealing member 240 is an elastic body and has the slit 242, when the through portion 161b passes through the through hole 241, the sealing member 240 is elastically deformed, and the slit 242 opens. Therefore, the reaction force caused by the deformation of the sealing member 240 when the through portion 161b passes through the through hole 241 is small, and it is possible to prevent the workability of replacing the drum cartridge 10 from being impaired.

[0045] When viewed from one end in the longitudinal direction, the passing portion 231 of the sealing member holding member 230 has a shape as shown in Fig. 12. That is, the passing portion 231 is a hole formed by a semicircular portion 231a having a semicylindrical outer diameter with a radius R3, a rectangular portion 231b having a substantially rectangular shape continuing from the semicircular portion 231a, and a notch portion 231c opening downward from the lower side of the rectangular portion 231b. The dimension of the rectangular portion 231b in the left-right direction in Fig. 12 is substantially the same as R3. The center of the semicircular portion 231a coincides with the center of the through-hole 241, and the notch 231 is formed at a position corresponding to the slit 242.

[0046] In this embodiment, the passing portion 231 is larger than the cross-sectional shape of the through portion 161b. That is, when the cross-sectional shape of the through portion 161b, which is a part of the light guide unit 16, is projected longitudinally onto the sealing member holding member 230, the cross-sectional shape of the through portion 161b is within the range of the passing portion 231, and the area of the passing portion 231 is larger than the cross-sectional area of the through portion 161b. Specifically, the radius R3 of the semicircular portion 231a of the passing portion 231 is larger than the radius R1 of the semicircular portion 162a of the light guide unit 16 shown in FIG. 6. That is, as shown in FIG. 14, R3>R1. In this embodiment, R3=4 mm.

[0047] With this configuration, there is a gap between the passing portion 231 and the outer peripheral surface of the light guide unit 16 that has passed through the passing portion 231, i.e., the outer peripheral surface of the through-hole 161b. As a result, when the drum cartridge 10 is attached to or detached from the apparatus main body 1A, it is possible to prevent the through-hole 161b of the light guide unit 16 from interfering with the sealing member holding member 230, and the attachment and detachment of the drum cartridge 10 can be performed smoothly.

[0048] In this embodiment, the gap between the passing portion 231 of the sealing member holding member 230 and the through portion 161b of the light guide unit 16 is set to be approximately 1.5 mm. Meanwhile, the dimensional difference (thickness) between the inner peripheral surface of the passing portion 231 and the inner peripheral surface of the through hole 241 of the sealing member 240 is set to be approximately 2 mm. Therefore, when the through portion 161b of the light guide unit 16 passes through the through hole 241 and the passing portion 231, the sealing member 240 elastically deforms by approximately 0.5 mm and abuts against the outer peripheral surface of the through portion 161b. This further improves the sealing performance of the sealing member 240.

[0049] The configuration of this embodiment as described above improves the sealing performance of the LED 210 without impairing the ease of replacing the drum cartridge 10. As a result, it is possible to reduce the intrusion of toner into the light-emitting portion of the LED 210 and suppress toner fusion to the surface of the LED 210.

[0050] In this embodiment, the shape of the passing portion 231 and the cross-sectional shape of the light guide unit 16 are as described above, but these shapes may be a circle, an ellipse, a combination of multiple arc shapes, or a polygon. In this case, the shape of the through hole 241 of the sealing member 240 may be a shape that matches these shapes, or may be a circle regardless of these shapes. The key is that the shape may be such that the inner circumferential surface of the through hole 241 of the sealing member 240 elastically abuts on the outer circumferential surface of the through portion 161b of the light guide unit 16 over substantially the entire circumference.

[0051] <Second embodiment> The second embodiment will be described with reference to Figures 15 to 19. In the first embodiment described above, the LED 210 is fixed, but in this embodiment, the LED 210 is configured to be supported so as to be movably supported. Since the other configurations and functions are the same as those of the first embodiment described above, the same configurations are assigned the same reference numerals and descriptions thereof will be omitted or simplified, and the following description will focus on the points that are different from the first embodiment.

[0052] As shown in Fig. 19, the optical static elimination device 200A of this embodiment includes a light guide unit 16 (see Figs. 17 and 18), a light source unit 201A, and a sealing member 240. Note that the light guide unit 16 is omitted in Fig. 19. The light source unit 201A is provided in the device main body 1A (see Fig. 1), and as shown in Fig. 15, includes an LED 210 as a light source, a support member 250 for supporting the LED 210, a light source holding member 260, and a biasing member 270. Materials and a spring 270 as a spring.

[0053] As shown in FIG. 16 , the support member 250 has a support plate 251, a protrusion 252, and a guide 253. The support plate 251 is a plate-like portion disposed in a substantially vertical direction and supports the LED 210 on one surface. The protrusion 252 is formed to protrude from the lower end of the support plate 251 toward the front side (the side that emits light) of the LED 210. As will be described later, when the drum cartridge 10 is attached, the protrusion 252 functions as an abutment portion, and a tip surface 252 a of the abutment portion abuts against one longitudinal end of the light guide unit 16. This forms a predetermined gap between the one longitudinal end of the light guide unit 16 and the LED 210. The guide 253 is a protrusion provided on both sides of the support plate 251 substantially parallel to the longitudinal direction in the width direction, which is perpendicular to the vertical and longitudinal directions.

[0054] The light source holding member 260 is provided in the apparatus main body 1A and holds the support member 250 so that it can move in the longitudinal direction. That is, in the present embodiment as well, the drum cartridge 10 is detachable from the apparatus main body 1A in the longitudinal direction, and the LEDs 210 supported by the support member 250 are movable in the same direction as the attachment / detachment direction of the drum cartridge 10 (insertion / removal direction X in FIG. 15 ). As shown in FIGS. 15 and 17 , the light source holding member 260 has a housing portion 261 that houses the support member 250 that supports the LEDs 210, and an engagement guide portion 262 that is engageable with a guide portion 253 of the support member 250 and guides the guide portion 253 in the longitudinal direction.

[0055] In this embodiment, the engagement guide portion 262 is a notch cut out along the longitudinal direction in a side plate that constitutes the accommodation portion 261. Then, a guide portion 253, which is a protrusion, is inserted into the notch, whereby the guide portion 253 and the engagement guide portion 262 are engaged with each other. Like the guide portion 253, the engagement guide portions 262 are formed on both sides in the width direction of the support member 250, and by engaging with the guide portions 253 on both sides, the engagement guide portions 262 support the support member 250 so that it can move in the longitudinal direction (insertion / removal direction X). In this state, the lower end portion of the support member 250 is floating above the bottom plate of the light source holding member 260. In this embodiment, such a configuration is called a floating configuration.

[0056] The spring 270 biases the support member 250 supporting the LED 210 in the direction opposite to the mounting direction of the drum cartridge 10, i.e., toward the other longitudinal end. That is, as shown in Figures 15 and 18, the spring 270 is disposed in an elastically compressed state between the support member 250 and a fixing portion 263 fixed to the light source holding member 260, and biases the support member 250 toward the other longitudinal end.

[0057] As described above, in this embodiment, the LED 210 is supported by the support member 250, which is movable in the insertion / removal direction X of the drum cartridge 10, and is biased by the spring 270 in the direction opposite to the insertion direction of the drum cartridge 10 into the apparatus main body 1A. Also in this embodiment, as shown in FIG. 6, the light guide unit 16 has a lower portion 164. The lower portion 164 is located in a position facing the protrusion 252 when the drum cartridge 10 is installed. As shown in FIG. 18, when the drum cartridge 10 is installed in the apparatus main body 1A, the abutment surface 164a of the lower portion 164 abuts against the tip surface 252a of the protrusion 252 of the support member 250.

[0058] Therefore, when the drum cartridge 10 is attached, after the abutting surface 164a of the light guide unit 16 abuts against the tip surface 252a of the protrusion 252 of the support member 250 that supports the LED 210, the light guide unit 16 and the LED 210 move together. At this time, the tip surface 252a and the abutting surface 164a abut against each other so that a predetermined gap (distance B) is formed between one longitudinal end of the light guide unit 16 and the LED 210. Therefore, regardless of variations in the attachment position of the drum cartridge 10 or variations in the dimensions of the light guide unit 16, variations in the distance (gap) between the incident surface 161a of the light guide unit 16 and the LED 210 can be reduced.

[0059] In the first embodiment described above, the LED 210 is fixed, so it is desirable to set the distance A between the incident surface 161a and the LED 210 taking into consideration variations in the mounting position of the drum cartridge 10. In contrast, in the present embodiment, the LED 210 is movable in the longitudinal direction, so even if the mounting position of the drum cartridge 10 is slightly shifted, the LED 210 moves accordingly. Therefore, the distance B between the incident surface 161a and the LED 210 can be made smaller than the distance A in the first embodiment.

[0060] As described above, in this embodiment, it is possible to reduce the variation in the distance B between the incident surface 161a of the light guide unit 16 and the LED 210, and also to reduce the distance B. This makes it possible to stabilize the amount of light incident from the LED 210 to the light guide unit 16, and also to reduce loss of the amount of incident light. As a result, it is possible to reduce the variation in the amount of static elimination light irradiated from the light guide unit 16 onto the photosensitive drum 12, thereby achieving a stable static elimination effect and improving the efficiency of the optical static elimination device.

[0061] 19, in the present embodiment, a sealing member 240 similar to that of the first embodiment is used to seal the gap between the drum container 11, inside which the photosensitive drum 12 is disposed, and the LED 210. Therefore, similar to the first embodiment, it is possible to improve the sealing performance of the LED 210 without impairing the workability of replacing the drum cartridge 10, and also to reduce variations in the amount of static elimination light and improve the efficiency of the optical static elimination device.

[0062] The floating configuration of the LED described in this embodiment is merely an example, and does not limit the guide shape, biasing means, etc., related to the floating configuration.

[0063] <Other embodiments> In the above-described embodiments, the optical static elimination device is configured to irradiate the surface of the photosensitive drum downstream of the primary transfer roller and upstream of the cleaning blade with light in the direction of rotation of the photosensitive drum to remove residual charge from the photosensitive drum. However, the present invention may also be configured such that the optical static elimination device irradiates the surface of the photosensitive drum with light before transferring the toner image from the photosensitive drum to the intermediate transfer belt. In this case, the light guide is disposed downstream of the developing unit and upstream of the primary transfer roller in the direction of rotation of the photosensitive drum.

[0064] In the above-described embodiments, the photosensitive unit is a drum cartridge. However, the photosensitive unit may be a process cartridge that is detachably mounted on the main body of the apparatus and that integrates the drum cartridge and the developing device. [Explanation of symbols]

[0065] 1···Image forming apparatus / 1A···Apparatus main body / 10···Drum cartridge (photosensitive unit) / 11···Drum container (photosensitive container) / 12···Photosensitive drum (photosensitive member) / 16···Light guide unit / 161···Light guide (light-guiding member) / 161a···incident surface / 161b···through-hole portion (part of light guide unit) / 162···protective member / 200, 200A···optical static elimination device / 201, 201A···light source unit / 210···LED (light source) / 220···light source holding member / 230···sealing member holding member (holding member) / 231···passing portion / 232···holding plate portion / 240···sealing member / 241···through hole / 242···slit / 250···supporting member / 252···protruding portion (contact portion) / 260···light source holding member / 270···spring (biasing Materials )

Claims

1. A device body, a photosensitive unit that includes a rotating photosensitive member and a light guide member that is disposed along the rotation axis direction of the photosensitive member and guides light incident from one end in the rotation axis direction to the surface of the photosensitive member, and that is detachable from the device main body by moving along the rotation axis direction; a light source provided in the device body and configured to irradiate light onto a light incident surface provided at the one end of the light guide member; a holding member that holds the light source and has a sealing member that is an elastic body having a through hole through which the one end of the light guide member is inserted and passes; Equipped with When the light-guiding member is inserted into the through hole, the inner surface of the through hole and the outer surface at the one end of the light-guiding member abut against each other, and the gap between the inner surface and the outer surface is sealed.

2. An image forming apparatus as described in Claim 1, characterized in that when the light-guiding member is inserted into the through hole, the entire circumference of the inner surface abuts against the light-guiding member.

3. The image forming apparatus described in Claim 1, characterized in that the image forming apparatus further comprises a biasing member that biases the light source toward the light-guiding member in the direction of the rotation axis.

4. An image forming apparatus as described in Claim 3, characterized in that the urging member is provided on the holding member.

5. 2. The image forming apparatus according to claim 1, wherein the sealing member seals the light source and the one end of the light guide member in the direction of the rotation axis when the light guide member is inserted into the through hole.

6. An image forming apparatus as described in claim 1, characterized in that the cross-sectional area of the through hole when the light-guiding member is not passing through is smaller than the cross-sectional area of the through hole when the light-guiding member is passing through.

7. An image forming apparatus as described in claim 1, characterized in that the through hole has a slit that continues toward the outside of the through hole.

8. The photosensitive unit has a photosensitive container that houses the photosensitive element, 2. The image forming apparatus according to claim 1, wherein the one end of the light guide member is a portion that protrudes outside the photosensitive member container in the direction of the rotation axis.

9. An image forming apparatus as described in claim 1, characterized in that the sealing member is a sponge.

10. An image forming apparatus as described in Claim 1, characterized in that the light source is an LED.

Images